WO2020034675A1 - Magnetic resonance imaging method for myocardial quantification, and device and storage medium therefor - Google Patents

Abstract

Disclosed are a magnetic resonance imaging method for myocardial quantification, and a device and a storage medium therefor. The method comprises: in each of recovery periods, performing an image signal acquisition operation under the control of an ECG gating signal and a respiratory navigation signal; determining a parameter T1 according to the image signal acquired and a delay time of a saturation pulse to which the image signal corresponds, and determining a parameter T2 according to the image signal acquired, a delay time of a saturation pulse to which the image signal corresponds, and an echo time interval of a T2 preparatory pulse; and generating a myocardial quantification magnetic resonance image according to parameters T1 and T2. The method can achieve scanning while a subject is breathing freely, avoiding the need for the subject to hold their breath. The method also further expands an imaging field and increases spatial resolution. Moreover, through complete alternating and segmented acquisition of sampling points in k-space, internal alignment of an original image is achieved, eliminating the need for later additional image processing.

Description

Quantitative myocardial magnetic resonance imaging method, equipment and storage medium Technical field

The present invention relates to the field of medical imaging, and more particularly, to a method, a device, and a storage medium for quantitative myocardial magnetic resonance imaging.

Background technique

MRI imaging of the human body using the phenomenon of MRI has been a common medical imaging examination.

The basic physical parameters of nuclear magnetic resonance, T ₁ (spin lattice relaxation time, or longitudinal relaxation time) and T ₂ (spin-spin relaxation time, or lateral relaxation time), describe longitudinal magnetization. Time constants for vector recovery and transverse magnetization vector decay processes. T ₁ and T _{2 are} determined by the composition of the biological tissue and the existing structural form and the magnetic field strength. Under a defined magnetic field strength, different tissues have specific T ₁ and T ₂ values. When biological tissues change, T ₁ and T ₂ also change. Therefore, T ₁ and T ₂ can be used as feature parameters to identify the characteristics of myocardial tissue.

The quantitative myocardial magnetic resonance imaging technology developed in recent years directly measures the basic physical parameters of magnetic resonance (represented by T ₁ and T ₂ ) to achieve quantitative myocardial tissue evaluation.

Cardiac quantitative magnetic resonance imaging technology includes single-parameter T ₁ or T ₂ imaging and 2D and 3D combined multi-parameter T ₁ and T ₂ imaging. Compared with single-parameter imaging, the combined parameter imaging method can obtain the measurement results of two parameters T ₁ and T _{2 in} one scan, and obtain more imaging information reflecting myocardial tissue.

In the existing technology capable of realizing quantitative cardiac imaging with the combined parameters T ₁ and T ₂ , the breath motion compensation during the scanning process is achieved by holding the breath. The breath-holding requirement restricts the further improvement of imaging resolution and cannot be used for subjects with breath-holding difficulties (this is more common in patients with heart disease). In the prior art, scan acceleration is performed by parallel imaging technology, which is at the expense of the signal-to-noise ratio of the signal, and complex down-sampling and reconstruction algorithms are introduced. Finally, more T ₁ and T ₂ weighted sampling points are required to be able to image, so it is sensitive to heart rate changes and has a long scan time. Before fitting the parameters, the original weighted image needs to be filtered. It is even necessary to perform motion correction (such as registration) on the original weighted image to eliminate the negative effects of myocardial motion on imaging.

Therefore, a new quantitative myocardial magnetic resonance imaging technique is urgently needed to solve the above problems at least in part.

Summary of the Invention

The present invention has been made in consideration of the above problems.

According to one aspect of the present invention, a quantitative myocardial magnetic resonance imaging method is provided, including:

Every recovery period, under the control of ECG gating signals and respiratory navigation signals, at least the following signal acquisition operations are performed:

In the first heartbeat, when it is determined according to the breathing navigation signal that the current moment meets a predetermined condition, collect a first image signal;

In the second heartbeat, after a saturation pulse with a delay time of Tsat2 is used, and when the current moment is determined to meet a predetermined condition according to the breathing navigation signal, a second image signal is acquired;

In the third heartbeat, a third image signal is acquired after a saturation pulse with a delay time of Tsat3 is used and the current moment is determined to meet a predetermined condition based on the respiratory navigation signal, where Tsat3 ≠ Tsat2;

In the fourth heartbeat, the saturation pulse using a delay time and the echo time is after Techo4 Tsat4 interval T ₂ of the preparation pulses, and a fourth image signal is acquired in a case where the current time satisfies the predetermined condition is determined in accordance with the respiratory navigation signals;

In the fifth heartbeat, the saturation pulse using a delay time and the echo time is Techo5 Tsat5 after a pulse interval T ₂ of the preparation, and the fifth image signal acquired in the case where the current time satisfies the predetermined condition is determined in accordance with the respiratory navigation signals;

In the sixth heartbeat, using the delay time and the echo time Tsat6 saturation pulse interval of T ₂ of Techo6 after preparation pulses, and sixth image signals acquired in the case where the current time satisfies the predetermined condition of the determination in accordance with the respiratory navigation signals, Among them, Tsat6 = Tsat5 = Tsat4, Techo6 ≠ Techo4, Techo6 ≠ Techo5, Techo5 ≠ Techo4, Techo4 is the echo time interval of the T ₂ preparation pulse used in the fourth heartbeat, and when not used in the fourth heartbeat When T _{2 is} ready to pulse, Techo4 = 0;

The parameter T _{1 is} determined according to the i-th image signal and the delay time Tsati of the saturation pulse corresponding to the i-th image signal, where i = 1, 2, 3, and when i = 1, Tsati is infinite; and according to the j-th image signal And the delay time Tsatj and T ₂ of the saturation pulse corresponding to the j-th image signal, the echo time interval Techoj of the preparation pulse determines the parameter T ₂ , where j = 4, 5, 6;

A quantitative myocardial magnetic resonance image is generated based on the parameter T ₁ and the parameter T ₂ .

According to another aspect of the present invention, there is also provided a device for quantitative myocardial magnetic resonance imaging, including a processor and a memory, wherein the memory stores computer program instructions, and the computer program instructions are received by the processor. The runtime is used to perform the above-mentioned quantitative myocardial magnetic resonance imaging method.

According to still another aspect of the present invention, a storage medium is further provided, and program instructions are stored on the storage medium, and the program instructions are used to execute the foregoing quantitative myocardial magnetic resonance imaging method when running.

The quantitative myocardial magnetic resonance imaging method, device, and storage medium according to the embodiments of the present invention can complete a scan without the subject having to hold his breath while the subject is breathing freely. It also allows to further expand the imaging field of view and improve the spatial resolution. In addition, the k-space is used to completely interleave segmented acquisitions between sampling points, thereby achieving the inherent registration of the original image without the need for additional image processing in the later stages.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more comprehensible. In the following, specific embodiments of the present invention are enumerated.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the present invention will become more apparent by describing the embodiments of the present invention in more detail with reference to the accompanying drawings. The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the description. They are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation on the present invention. In the drawings, the same reference numbers generally represent the same components or steps.

FIG. 1 shows a schematic flowchart of a quantitative myocardial magnetic resonance imaging method according to an embodiment of the present invention;

Figure 2 shows an imaging sequence according to an embodiment of the invention;

FIG. 3 shows a T ₁ estimation curve according to an embodiment of the present invention;

FIG. 4 shows a T ₂ estimation curve according to an embodiment of the present invention;

5 illustrates an imaging sequence according to yet another embodiment of the present invention;

Figure 6 shows an imaging sequence according to another embodiment of the invention; and

Fig. 7 shows an imaging sequence according to a further embodiment of the invention.

detailed description

In order to make the objectives, technical solutions, and advantages of the present invention more obvious, an exemplary embodiment according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments of the present invention. It should be understood that the present invention is not limited by the exemplary embodiments described herein. Based on the embodiments of the present invention described in the present invention, all other embodiments obtained by those skilled in the art without paying any creative effort should fall within the protection scope of the present invention.

According to an embodiment of the present invention, a quantitative myocardial magnetic resonance imaging method is provided. This method is a 3D free breathing quantitative myocardial parameter T ₁ and T ₂ combined imaging technology. This technology uses breathing navigation technology to achieve compensation for breathing movements. Through the use of saturation pulses, combined with sufficient T ₁ recovery time to obtain an ideal steady state magnetization vector, it is insensitive to heart rate changes and can achieve higher T ₁ and T ₂ fitting accuracy. The k-space staggered segmented acquisition method is used to achieve the intrinsic self-registration of the original image, without the need for post-processing such as registration and filtering of the original image, and without the need for parameter correction. Accurate measurement of ₁ and T ₂ .

FIG. 1 shows a schematic flowchart of a quantitative myocardial magnetic resonance imaging method 100 according to an embodiment of the present invention. As shown in FIG. 1, the quantitative myocardial magnetic resonance imaging method 100 includes the following steps.

In step S110, a signal acquisition operation is performed under the control of the ECG gating signal and the respiratory navigation signal every recovery period.

This signal acquisition operation can acquire multiple imaging sequences in a cyclic manner. Every cycle, an imaging sequence is acquired. Each imaging sequence includes multiple image signals. In one example, each imaging sequence includes 6 image signals. k-space is the data space for magnetic resonance acquisition. Each time the image signal acquisition of an imaging sequence is completed, a segmented filling of k-space in magnetic resonance imaging is achieved. The imaging sequence needs to be acquired cyclically several times in order to fill the complete k-space for reconstruction of the image. It can be understood that the parallel sampling technique and the K-space downsampling technique in any other manner can be adopted.

The signal acquisition operation is based on an electrocardiogram (ECG). The ECG can be obtained by attaching electrodes to the surface of the subject's chest skin and by using an ECG monitoring device. In an electrocardiogram, the time interval between two R waves is called a beat, which is the cardiac cycle. The next heartbeat can be determined by detecting the R wave. Each image signal in the imaging sequence is acquired separately during a cardiac cycle. In the example where the imaging sequence includes 6 image signals, 6 heartbeats are needed to complete the signal acquisition.

There is an image signal in the imaging sequence that allows the longitudinal magnetization vector to fully recover to a steady state. For simplicity of description, it is referred to as a steady-state image signal for short. In order to enable the longitudinal magnetization vector to be completely recovered after the acquisition operation of the previous imaging sequence, before the acquisition of the steady-state image signal, a recovery period is set, such as n idle heartbeats, or called recovery heartbeats. During this recovery period, no image signal is collected, and no operation that may disturb the recovery process of the magnetization vector is performed.

The aforementioned number of idle heart beats n can be determined according to the length of time that the magnetization vector is allowed to recover and the subject's heart rate. The time length N (seconds) that allows the magnetization vector to be restored can be set by the user in real time online, which indirectly determines the time position of the steady-state image signal on the T ₁ estimation curve. The larger N is, the more the magnetization vector is recovered. Therefore, more ideal steady-state data can be obtained, which is beneficial to improving the accuracy of the parameters T ₁ and T ₂ . However, the larger N, the longer the scanning time required for imaging. Therefore, it is necessary to set N based on both the scanning efficiency and the accuracy of the steady state value. In one example, the magnetic field strength is 3T, and the minimum idle time can be set to 6 seconds (ie, N = 6). This can guarantee the recovery of more than 95% of the magnetization vector. If the magnetic field strength is 1.5T, N can be reduced accordingly. By setting the time length N that allows the magnetization vector to recover instead of the number of idle heartbeats n in real time, it is possible to strip the association with the change in heart rate while ensuring that the signal returns to a steady state.

According to an embodiment of the present invention, the number of idle heart beats n ≧ N / (60 / HR), wherein the subject's heart rate is HR (heartbeat / minute), and the length of time allowed for the magnetization vector to recover is N seconds. Optionally, n takes the smallest integer greater than or equal to N / (60 / HR). The number of idle heartbeats determined by this formula can ensure that the magnetization vector can be fully recovered. Furthermore, the accuracy of the generated quantitative myocardial magnetic resonance image is guaranteed.

In each heartbeat, the time of acquiring the image signal is determined according to the ECG gating signal. After the time period Ttrigger has elapsed since the R peak, image signals are collected. The moment when the image signal is expected to be collected is the moment when the heart is relatively still, such as a moment at the end of the diastole. The ECG gating technology can make the acquired image signals less disturbed by cardiac motion. It can be understood that the time period Tgrigger can be set by the scanner according to experience.

According to an embodiment of the present invention, in each heartbeat, it is also determined whether to acquire an image signal according to a breathing navigation signal. By monitoring changes in the position of the pectoralis diaphragm with breathing motion, it is possible to indirectly estimate changes in the position of the heart with breathing motion. In the embodiment of the present invention, the respiratory navigation signal is collected within a short period of time (NAV) before the time period Trigrigger starts from the R peak of the ECG gating signal. According to the breathing navigation signal, it is determined whether the current time meets a predetermined condition, that is, whether the position of the pectoralis diaphragm at the current time is at a desired position. Therefore, it is judged whether the image signal collected after the time period Trigrigger of the ECG gated signal starts to meet the requirements of respiratory motion compensation, that is, whether the image signal collected in the heartbeat is valid. Using respiratory navigation technology, subjects can breathe freely during quantitative myocardial magnetic resonance imaging. It also expands the imaging field of view and improves the spatial resolution of the image.

Step S120, the delay time in accordance with a first portion of the image signal acquired in step S110 and a first portion of the image signal which respectively corresponding to saturation pulse to determine the parameters T _1. Before acquiring an image signal, a saturation pulse can be applied. For a heartbeat without applying a saturation pulse, the delay time corresponding to the image signal acquired in the heartbeat can be set to an infinite saturation pulse. The weight of the parameter T ₁ can be changed by applying saturation pulses of different delay times. The use of a saturation pulse reduces the dependence of the image signal on changes in heart rate.

The parameter T ₂ is determined according to the second part of the image signal collected in step S110 and the delay time of the saturation pulse and the echo time interval of the T ₂ preparation pulse respectively corresponding to the second part of the image signal. Before the image signal is acquired, in addition to the saturation pulse, a T ₂ preparation pulse may be applied. T ₂ is not applied to the heart beat preparation pulses, may be provided within the image signal corresponding to the acquired heartbeat T ₂ preparation pulse-echo time interval is zero. The weight of the parameter T ₂ can be changed by applying T ₂ preparation pulses at different echo time intervals.

In the above steps, different data fitting methods can be used to determine the parameters T ₁ and T ₂ . Optionally, different signal models are used to fit the parameters T ₁ and T ₂ respectively based on the sampling points (ie, image signals). In this case, the signal model fitting of T ₁ and T ₂ are independent of each other, and there is no problem of transmission interference of the two parameter fitting errors. Alternatively, a signal model may also be used to jointly fit the parameters T ₁ and T ₂ .

Step S130, the step S120 in accordance with the determined parameter T ₁ and T ₂ are generated quantitative cardiac MR images. In this step, a quantitative myocardial magnetic resonance image can be generated based on the parameters T ₁ and T ₂ obtained by the fitting operation.

According to the above-mentioned imaging method 100 according to the embodiment of the present invention, the simultaneous measurement of the 3D quantitative parameters T ₁ and T ₂ is achieved. For the subject's heart motion and breathing motion, compensation for the above motion is achieved through ECG gating and breathing navigation, thereby ensuring that image signals are acquired on the same breathing state and cardiac motion cycle. The scan can be done while the subject is breathing freely without the need to hold his breath. It also allows to further expand the imaging field of view and improve the spatial resolution. In addition, in the above-mentioned imaging method 100, k-space is used to acquire samples in a completely staggered and segmented manner between sampling points, thereby realizing the intrinsic registration of the original image and eliminating the need for additional image processing at a later stage.

Figure 2 shows an imaging sequence according to an embodiment of the invention. It can be understood that a plurality of such imaging sequences are obtained in a circular manner in the embodiment of the present invention. In each imaging sequence, a total of 6 image signals were acquired. Within each heartbeat, under the control of the ECG gating signal and the respiratory navigation signal, different signal acquisition operations are performed to obtain an image sequence. The image signal acquisition process is the k-space filling process in magnetic resonance imaging.

As shown in FIG. 2, in the first heartbeat, when it is determined that the current time meets a predetermined condition according to the breathing navigation signal, a first image signal IMG _{1 is} collected. The first image signal IMG ₁ is a value in which the longitudinal magnetization vector is sufficiently restored to a steady state. That is, the first image signal IMG ₁ is the above-mentioned steady-state image signal.

Within this first heartbeat, no saturation pulse is used. It may be provided corresponding to a first image signal IMG _delay time infinity saturation pulse, i.e. Tsat1 is infinite.

It can be understood that, within the first heartbeat, it is determined according to the breathing navigation signal that the current time meets a predetermined condition. Prior to the first heartbeat, there may be a heartbeat during which the current moment is determined not to meet the predetermined conditions based on the breathing navigation signal. Therefore, optionally, in the signal acquisition operation, before the first heartbeat, the following operation is further included: in one heartbeat, if it is determined that the current time does not meet the predetermined condition according to the breathing navigation signal, wait for the next heartbeat to repeat A judgment operation is performed according to the breathing navigation signal, and a corresponding image signal acquisition operation of the current heartbeat is performed according to the judgment result. For the convenience of description, the heartbeat during which the current moment does not meet the predetermined conditions according to the breathing navigation signal is referred to as the A heartbeat. In A heartbeat, no image signal acquisition is performed. In the next heartbeat of the A heartbeat, it is determined again whether the current time meets a predetermined condition according to the breathing navigation signal. If it still does not match, then continue to wait. Until a certain heartbeat determines that the current time meets a predetermined condition according to the breathing navigation signal, the heartbeat is the first heartbeat. As described above, in the first heartbeat, when it is determined that the current time meets a predetermined condition according to the breathing navigation signal, the first image signal IMG _{1 is} acquired.

In the above scheme, in the A heartbeat before the first heartbeat, no image signal is collected. Therefore, it can be ensured that the magnetization vector collected in the first heartbeat is a value in its equilibrium state.

In the second heartbeat, a saturation pulse SAT with a delay time Tsat2 is used first. The saturation pulse can zero the magnetization vector. As shown in FIG. 2, the delay time of the saturation pulse is the time interval between the saturation pulse and the time when the image signal is collected. After using the saturation pulse SAT with a delay time of Tsat2, the second image signal IMG ₂ is acquired in a case where it is determined that the current time meets a predetermined condition according to the respiratory navigation signal.

Similar to the second heartbeat, in the third heartbeat, a third image signal IMG ₃ is acquired after a saturation pulse with a delay time of Tsat3 is used and the current time is determined to meet a predetermined condition based on the breathing navigation signal. Among them, Tsat3 ≠ Tsat2.

In the second and third heartbeats, T ₁ weighting is achieved using saturation pulses. Among them, the delay time of the saturation pulse is different, and the weight of T ₁ is different. Thus, one sampling point was obtained in each of the two heartbeats. The delay time of the saturation pulse can be any value from the minimum time interval allowed by the system to the maximum time interval allowed by the system.

Optionally, the delay time Tsat2 of the saturation pulse in the second heartbeat is 35% to 70% of the maximum time interval Tmax allowed by the system. The sum of the length of time occupied by the signal operation (eg, the respiratory navigation signal NAV) and the hardware response delay time during the Ttrigger period can be determined first. Then calculate the difference between the time period Ttrigger and the sum, which is the maximum time interval Tmax allowed by the system. The delay time Tsat3 of the saturation pulse in the third heartbeat is 90% to 100% of the maximum time interval Tmax allowed by the system. According to an embodiment of the present invention, Tsat2 is Tmax / 2, and Tsat3 is equal to Tmax. Tmax, the longer the recovery time of the magnetization vector, also can be used for forming an image signal is stronger, the larger the ratio (SNR) of image signals obtained, the greater the weight of the weight of ₁ T. FIG. 3 shows a T ₁ estimation curve according to this embodiment. Among them, the horizontal axis represents the delay time of the saturation pulse, the vertical axis represents the normalized longitudinal magnetization vector (Mz) that can be used for data reading, and the steady state value of the longitudinal magnetization vector when Mz = 1. The sampling points IMG ₁ , IMG ₂ and IMG ₃ obtained in the first, second and third heartbeats are also shown in FIG. ₃ . These sampling points belong to the first part of the image signal involved in the method 100. Tsat2 and Tsat3 use the above range of values to make the sampling points more reasonably distributed, so that the T ₁ value can be accurately estimated even when only a small number of sampling points are obtained. In addition, the above-mentioned value range also makes the longitudinal magnetization vector that can be used for data reading larger, thereby improving the signal-to-noise ratio of the signal and obtaining a better quality original weighted image.

In the fourth heartbeat, similar to the second and third heartbeats, a saturation pulse with a delay time of Tsat4 is used first. Alternatively, using a delay time after the saturation pulse SAT Tsat4 may be prepared without the use of pulse T _2, as shown in FIG. In this case, Techo4 = 0. After using the saturated pulse SAT, in a case where it is determined that the current time meets a predetermined condition according to the respiratory navigation signal, a fourth image signal IMG _{4 is} acquired.

Optionally, the delay time Tsat4 of the saturation pulse SAT in the fourth heartbeat is 90% to 100% of the maximum time interval Tmax allowed by the system. In this case, since Tsat6 = Tsat5 = Tsat4, Tsat6 and Tsat5 are also in the same value range. The delay time of the saturation pulse in the fourth heartbeat, the fifth heartbeat, and the sixth heartbeat can significantly improve the image quality within the above-mentioned value range. It can be understood that the value range is only an example and not a limitation on the present invention. In fact, the delay time of the saturation pulse in the fourth heartbeat, the fifth heartbeat, and the sixth heartbeat can take any possible value.

In the fifth and sixth heartbeats, the saturation pulses with delay times Tsat5 and Tsat6, respectively, are used first. Then prepare the pulse T ₂ -prep for T ₂ of Techo 5 and Techo 6 with echo time interval. The T ₂ preparation pulse T ₂ -prep is used to achieve T ₂ attenuation of the magnetization vector. By changing the interval T ₂ T ₂ -prep preparation pulse echo time, T ₂ of different levels to achieve attenuation. In the preceding first, second, and third heartbeats, there is no T ₂ preparation pulse T ₂ -prep. In the fourth heartbeat, T ₂ may be present or absent preparation pulses T ₂ -prep. In the case where there is no T ₂ preparation pulse, as described earlier, the delay time of the saturation pulse is the time interval between the saturation pulse and the time when the image signal is acquired. In the case where the T ₂ preparation pulse is present, the delay time of the saturation pulse is a time interval between the saturation pulse and the T ₂ preparation pulse T ₂ -prep. Before using T _{2 to} prepare the pulse, it can be determined whether the current time meets the predetermined condition according to the breathing navigation signal. The delay time of the saturation pulse in the fifth heartbeat and the sixth heartbeat is equal to the delay time of the saturation pulse in the fourth heartbeat, that is, Tsat6 = Tsat5 = Tsat4. However, the echo time intervals Techo4, Techo5, and Techo6 of the T ₂ preparation pulses in the fourth heartbeat, the fifth heartbeat, and the sixth heartbeat are not equal. That is, Techo5 ≠ Techo4, Techo6 ≠ Techo4, Techo5 ≠ Techo6. Thus, changes in the magnetization vector used for imaging within the fourth, fifth, and sixth heartbeats are different from each other. In the fifth heartbeat, using the delay time and the echo time Tsat5 saturation pulse interval T ₂ is after Techo5 preparation pulses, and in the case where the current time satisfies the predetermined condition of the determination in accordance with the respiratory navigation signals, a fifth image capture signal IMG ₅ . In the sixth heartbeat, also in a similar case, a sixth image signal IMG _{6 is} acquired. That is, the sixth image signal IMG ₆ is acquired after using a saturation pulse with a delay time of Tsat 6 and a pulse of T ₂ with an echo time interval of Techo 6 and determining that the current time meets a predetermined condition based on the respiratory navigation signal.

In the above-mentioned heartbeat in which the T ₂ preparation pulse exists, not only the T ₁ weighting is realized by using the saturation pulse, but also the T ₂ weighting is realized by using the T ₂ preparation pulse. The T ₂ weight is changed by changing the echo time interval of the T ₂ preparation pulse. In FIG. 2, a pulse echo time interval of T ₂ preparation expressed as T represents T ₂ preparation pulse width of the rectangle of ₂ -prep. The echo time interval of the T ₂ preparation pulse can be determined according to the sampling points on the T ₂ attenuation curve that can better describe the curve shape. Such sampling points are, for example, sampling points at which the echo time intervals of the corresponding T ₂ preparation pulses are 0 and the estimated value of myocardial T ₂ respectively, and the sampling points centered between the two sampling points. As described above, if the T ₂ preparation pulse is not used in the fourth heartbeat, the echo time interval of the T ₂ preparation pulse corresponding to the fourth image signal IMG ₄ collected in the fourth heart beat is 0, and the fourth image signal IMG ₄ Is the point where the magnetization vector is the largest on the T ₂ decay curve. Optionally, the echo time interval Techo5 of the T ₂ preparation pulse in the sixth heartbeat is 90% to 110% of the estimated value of the myocardial T _{2 in the} current magnetic field intensity, and the echo time interval Techo5 of the T ₂ preparation pulse in the fifth heartbeat is 35% to 70% of Techo6 or the minimum T ₂ ready pulse echo time interval allowed by the system. For example, in the case where the magnetic field strength is 3T, the T _{2 of the} myocardium is about 42 ms, so in this example, the echo time interval of the T ₂ preparation pulse in the sixth heartbeat is Techo6 = 45 ms. Regarding the echo time interval Techo5 of the T ₂ preparation pulse in the fifth heartbeat, it is desirable to take an intermediate value between 0 and 45 ms, so that it can better reflect the shape of the T ₂ attenuation curve. Therefore, Techo5 = 25ms can be set. FIG. 4 shows a T ₂ estimation curve according to this embodiment. Among them, the horizontal axis represents the echo time interval of the T ₂ preparation pulse, the vertical axis represents the normalized longitudinal magnetization vector (Mz) that can be used for data reading, and the steady state value of the longitudinal magnetization vector when Mz = 1. As shown in FIG. 4, the right part of the point corresponding to the maximum time interval Tmax allowed by the system is the T ₂ attenuation curve. Figure 4 shows the sampling points obtained in the fourth, fifth and sixth heartbeats, respectively. These sampling points belong to the second part of the image signal involved in the method 100. Techo5 and Techo6 use the above range to make the sampling points more evenly distributed on the T ₂ attenuation curve, so that T ₂ can be more accurately estimated even when only a small number of sampling points are obtained. It can be understood that the echo time interval of the T ₂ preparation pulse can be preset by the user.

Similar to the first heartbeat, before one or more of the second, third, fourth, fifth, and sixth heartbeats, there may be a heartbeat during which it is determined that the current moment does not meet a predetermined condition according to the breathing navigation signal. Optionally, in the signal acquisition operation, before the one or more of the second, third, fourth, fifth, and sixth heartbeats, the following operation is further included: within one heartbeat, determining according to the breathing navigation signal If the current time does not meet the predetermined conditions, acquire the image signal and make the acquired image signal invalid, wait for the next heartbeat to perform the judgment operation based on the breathing navigation signal again and perform the corresponding image signal acquisition of the current heartbeat according to the judgment result operating. If misjudgment occurs, the acquired image signal can be used as raw data. This ensures the completeness of the imaging data.

Taking the second heartbeat as an example, it is assumed that, before the second heartbeat, there is a heartbeat during which it is determined that the current time does not meet the predetermined condition according to the breathing navigation signal, which is referred to as the B heartbeat for short. In the next heartbeat of the B heartbeat, it is determined again whether the current time meets a predetermined condition according to the breathing navigation signal. If it still does not match, then acquire the image signal and disable the acquired image signal, and continue to wait for the next heartbeat. Until a certain heartbeat determines that the current time meets a predetermined condition according to the breathing navigation signal, the heartbeat is a second heartbeat. As described above, in the second heartbeat, the second image signal IMG ₂ is acquired after a saturation pulse with a delay time of Tsat2 is used and the current time is determined to meet a predetermined condition based on the respiratory navigation signal.

In the above signal acquisition operation, image signals with different T ₁ weights (IMG ₁ , IMG ₂ and IMG ₃ ) and image signals with mixed T ₁ -T ₂ weights (IMG ₄ , IMG ₅ and IMG ₆ ) are collected. These image signals are acquired cyclically. That is, after completing the IMG ₆ acquisition of the sixth heartbeat, return to the first heartbeat. Then, the above process is repeated. In other words, during the imaging process, the above-mentioned imaging sequence is repeatedly acquired until the filling of all segments of the k-space in the magnetic resonance imaging is completed. It can be understood that the sequence of the first heartbeat to the sixth heartbeat is merely an example, rather than a limitation on the present invention. These 6 heartbeats can be performed in any order without affecting the effect of the technical solution of the present application.

As mentioned earlier, a steady-state image signal is acquired in the first heartbeat. In order to make the longitudinal magnetization vector completely recover from the last image signal acquisition (IMG ₅ ), before the first heartbeat, a recovery time period is set. During this recovery period, no image signal is acquired. Optionally, during this recovery period, only the respiratory navigation signal NAV is collected to ensure the continuity of the respiratory navigation signal. As a result, interference with the parameter setting of the NAV and the flexibility it provides is avoided. This further ensures that the breathing navigation signal NAV accurately controls the signal acquisition operation to obtain a more accurate image signal.

Fig. 5 shows an imaging sequence according to a further embodiment of the invention. The imaging sequence shown in FIG. 5 is similar to the imaging sequence shown in FIG. 2. For the sake of brevity, the same parts in the two imaging sequences will not be described again. The main difference between the two is the fourth heartbeat in the imaging sequence. 5, in a fourth heartbeat, after the saturation pulse using a delay time of SAT Tsat4 using echo time interval T ₂ of Techo4 preparation pulses T ₂ -prep. After using the saturation pulse SAT and the T ₂ preparation pulse T ₂ -prep, in a case where it is determined that the current time meets a predetermined condition based on the respiratory navigation signal, a fourth image signal IMG _{4 is} acquired.

Through the optimized imaging sequence, the imaging method 100 has high scanning efficiency and unlimited imaging resolution. Only a few sampling points are needed, for example, only the above six sampling points of IMG ₁ , IMG ₂ , IMG ₃ , IMG ₄ , IMG ₅ and IMG ₆ can realize the simultaneous measurement of 3D myocardial quantitative parameters T ₁ and T ₂ , And no additional filtering data processing is required.

It can be understood that the above-mentioned collected image signals (IMG ₁ , IMG ₂ , IMG ₃ , IMG ₄ , IMG ₅ and IMG ₆ ) can utilize various suitable data reading methods. The data reading method includes, but is not limited to, gradient echo, echo echo imaging (Echo-Planar Imaging, EPI), and spin echo (Spin Echo). Preferably, the data reading method adopts spoiled gradient echo (SPGR), balanced Steady state free precession (bSSFP), and gradient spin echo (Grase) techniques. The adoption of these preferred data reading methods can significantly reduce the requirements of the magnetic field intensity uniformity during the imaging process, so that this solution can be applied to high-field (such as 3T) magnetic resonance systems.

Fig. 6 shows an imaging sequence according to another embodiment of the invention. The imaging sequence shown in FIG. 6 is similar to the imaging sequence shown in FIG. 2. For the sake of brevity, the same parts in the two imaging sequences will not be described again. As shown in FIG. 6, before the image signal (IMG ₁ , IMG ₂ , IMG ₃ , IMG ₄ , IMG _5, and IMG ₆ ) is acquired in the signal acquisition operation, a liposuction operation (FS) may be performed separately. Fig. 7 shows an imaging sequence according to a further embodiment of the invention. The imaging sequence shown in FIG. 7 is similar to the imaging sequence shown in FIG. 5. For the sake of brevity, the same parts in the two imaging sequences will not be described again. As shown in FIG. 7, before the image signal (IMG ₁ , IMG ₂ , IMG ₃ , IMG ₄ , IMG ₅ and IMG ₆ ) is acquired in the signal acquisition operation, the fat-pressing operation (FS) is also performed separately. Liposuction helps reduce respiratory artifacts and significantly improves imaging quality.

According to an embodiment of the present invention, the parameter T ₁ may be determined according to the i-th image signal and the saturation pulse delay time Tsati of the i-th image signal, where i = 1, 2, 3. And when i = 1, Tsat1 used for data fitting is infinite.

其中，i＝1、2、3。S _i和Tsati分别是信号采集操作所获得的第i图像信号和其对应的饱和脉冲的延迟时间。S ₀是磁化向量在平衡态时的理论图像信号。S ₀与T ₁在此公式中是未知的。根据IMG ₁、IMG ₂和IMG ₃能够确定这二者。根据该公式能够更准确地确定参数T ₁，从而生成更准确的图像。 In one example, the parameter T ₁ is determined according to the following formula,

Among them, i = 1, 2, 3. S _i and Tsati are respectively the ith image signal obtained by the signal acquisition operation and the delay time of its corresponding saturation pulse. S ₀ is a theoretical image signal when the magnetization vector is in an equilibrium state. S ₀ and T ₁ are unknown in this formula. Both can be determined from IMG ₁ , IMG ₂ and IMG ₃ . According to this formula, the parameter T ₁ can be determined more accurately, thereby generating a more accurate image.

The parameter T ₂ can be determined according to the echo time interval Techoj of the pulse prepared according to the j-th image signal and the saturation pulse delay times Tsatj and T _{2 of} the j-th image signal, where j = 4, 5, 6.

其中，j＝4、5、6。S _j和Tehoj分别是信号采集操作所获得的第j图像信号和其对应的T ₂准备脉冲的回波时间间隔。S _M是在延迟时间为Tsat3的饱和脉冲的作用下的纵向磁化矢量的信号。S _M与T ₂在此公式中是未知的。根据IMG ₄、IMG ₅和IMG ₆能够确定这二者。根据该公式能够更准确地确定参数T ₂，从而生成更准确的图像。 In one example, the parameter T ₂ is determined according to the following formula,

Here, j = 4, 5, and 6. S _j and Tehoj are respectively the j-th image signal obtained by the signal acquisition operation and the echo time interval of its corresponding T ₂ preparation pulse. S _M is a signal of the longitudinal magnetization vector under the action of a saturation pulse with a delay time of Tsat3. S _M and T ₂ are unknown in this formula. Both can be determined from IMG ₄ , IMG _5, and IMG ₆ . According to this formula, the parameter T ₂ can be determined more accurately, thereby generating a more accurate image.

For healthy subjects, in the T ₁ and T ₂ images generated according to the embodiments of the present invention, the numerical distribution of the parameters T ₁ and T ₂ presents a normal distribution. Moreover, the standard deviations of the values of the parameters T ₁ and T ₂ are small. Therefore, the quantitative myocardial magnetic resonance image generated according to the embodiment of the present invention ideally reflects the state of the myocardial tissue of the subject.

Optionally, the above-mentioned signal acquisition operation further includes at least one of the following operations: within the f1 heartbeat, after using a saturation pulse with a delay time of Tsatf1, and acquiring a condition that the current time meets a predetermined condition according to the breathing navigation signal, For image signals, Tsatf1 is not equal to the delay time of saturation pulses corresponding to other image signals, and f1 is an integer that is not equal to 1, 2, 3, 4, 5, and 6. For example, one image signal may be acquired in each of the seventh heartbeat and the eighth heartbeat. This operation is similar to the above-mentioned operation of collecting IMG ₂ and IMG _3. For brevity, details are not described herein again. With this operation, the sampling points are increased.

It can be understood that the above-mentioned determination parameter T _{1 is} also based on the f1-th image signal and Tsatf1. Therefore, more accurate parameters T ₁ can be obtained by more sampling points participating in the fitting.

The above-described operation with respect to the first image signal f1 is a parameter T _1, ie. Similarly, the signal acquisition operation further includes at least one of the following operations on the parameter T ₂ : within the g1 heartbeat, after using a saturation pulse with a delay time of Tsatg1 and an echo preparation interval of T ₂ of Techog1, and G1 image signal is collected when it is judged that the current moment meets the predetermined conditions according to the respiratory navigation signal, where Tsatg1 = Tsat4, Techog1 is not equal to the echo time interval of the T ₂ preparation pulse corresponding to other image signals, and g1 is not equal to 1, Integers of 2, 3, 4, 5, and 6. It can be understood that if the f1-th image signal is also acquired in the imaging method, g1 is not equal to f1. The determination parameter T _{2 is} also based on the g1-th image signal and the Techog1.

Therefore, more accurate parameters T ₂ can be obtained by more sampling points participating in the fitting.

Optionally, the signal acquisition operation further includes at least one of the following operations: in the f2 heartbeat, after using a saturation pulse with a delay time of Tsat2 or Tsat3, and in determining that the current moment meets a predetermined condition according to the breathing navigation signal A second image signal or a third image signal corresponding to the saturation pulse is acquired again, and f2 is an integer not equal to 1, 2, 3, 4, 5, and 6. It can be understood that if f1 and g1 image signals are also acquired in the imaging method, f2 is not equal to f1 and g1. This operation is an operation of repeating the second heartbeat or the third heartbeat, thereby obtaining sampling points with the same T ₁ weight. Finally, the parameter T _{1 is} determined from all the acquired second image signals and / or all the third image signals. For example, a second image signal input signal model acquired multiple times is fitted to obtain a parameter T ₁ .

Regarding the parameter T ₂ , there may be similar steps. Optionally, the signal acquisition operation further includes at least one of the following operations: within the g2 heartbeat, using a saturation pulse with a delay time of Tsat4 and a T ₂ preparation pulse with an echo time interval of Techo4 (if any), using after the delay time and the echo time Tsat5 saturation pulse interval T ₂ of Techo5 as preparation pulses or time delay and echo time Tsat6 saturation pulse interval T ₂ is Techo6 preparation pulses, and is determined in accordance with the respiratory signal of the current navigation When the time meets the predetermined condition, the fourth image signal, the fifth image signal, or the sixth image signal corresponding to the saturation pulse is acquired again, and g2 is an integer not equal to 1, 2, 3, 4, 5, or 6. It can be understood that if f1, g1, and f2 image signals are also acquired in the imaging method, g2 is not equal to f1, g1, and f2. For example, in the ninth heartbeat, after a saturation pulse having a delay time of Tsat4 is used, and if it is determined that the current time meets a predetermined condition based on the respiratory navigation signal, a fourth image signal corresponding to the saturation pulse is acquired again. In the tenth heartbeat, using the delay time and the echo time Tsat5 saturation pulse interval T ₂ is after preparation pulses Techo5 and respiratory navigation signal determines when the current time satisfies the predetermined condition and again collected saturation pulse according to a corresponding The fifth image signal. In the eleventh heartbeat, the saturation pulse using a delay time and the echo time is after Tsat6 interval T ₂ Techo6 preparation pulses, and collected again in the case where the current time satisfies the predetermined condition of the respiratory navigation signal pulse is determined in accordance with a saturated The corresponding sixth image signal. Finally, the parameter T _{2 is} determined from all the acquired fourth image signals and / or all the fifth image signals. In the above example, the fourth image signal acquired in the fourth heartbeat, the ninth heartbeat, the fifth image signal acquired in the fifth heartbeat, the tenth heartbeat, and the sixth image acquired in the sixth heartbeat and the eleventh heartbeat. All signals are input to the signal model and fitted to determine the parameter T ₂ .

The effect of the above technical solution is equivalent to averaging the noise of the sampling point (for example, the second image signal), thereby reducing the fitting bias. In short, the above signal acquisition operation can improve the calculation accuracy of the parameters T ₁ and T ₂ , thereby improving the image quality.

According to yet another aspect of the present invention, an apparatus for quantitative myocardial magnetic resonance imaging is also provided. The system includes a processor and a memory. The memory stores computer program instructions for implementing each step in the method for quantitative myocardial magnetic resonance imaging according to an embodiment of the present invention. The processor is configured to execute computer program instructions stored in the memory to perform corresponding steps of a method for quantitative myocardial magnetic resonance imaging according to an embodiment of the present invention.

According to still another aspect of the present invention, a storage medium is further provided, and program instructions are stored on the storage medium, and when the program instructions are executed by a computer or a processor, the computer or the processor executes an embodiment of the present invention. Corresponding steps of the method for quantitative myocardial magnetic resonance imaging and used to implement corresponding modules in the apparatus for quantitative myocardial magnetic resonance imaging according to an embodiment of the present invention. The storage medium may include, for example, a storage part of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disk read-only memory (CD-ROM), USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.

In the description provided here, numerous specific details are explained. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of the specification.

Similarly, it should be understood that, in order to streamline the invention and help understand one or more of the various aspects of the invention, in describing the exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, diagram, , Or in its description. However, the method of the present invention should not be construed to reflect the intention that the claimed invention requires more features than those explicitly recited in each claim. Rather, as reflected by the corresponding claims, the invention is that the corresponding technical problem can be solved with features that are less than all the features of a single disclosed embodiment. Thus, the claims following a specific embodiment are hereby explicitly incorporated into this specific embodiment, wherein each claim itself is a separate embodiment of the present invention.

Those skilled in the art can understand that, in addition to the mutual exclusion of features, all combinations of all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and any method or device so disclosed can be adopted in any combination. Processes or units are combined. Each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

In addition, those skilled in the art can understand that although some embodiments described herein include certain features included in other embodiments and not other features, the combination of features of different embodiments is meant to be within the scope of the present invention Within and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

It should be noted that the word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The use of the words first, second, and third does not imply any order. These words can be interpreted as names.

The above description is only a specific embodiment of the present invention or a description of the specific embodiment, and the protection scope of the present invention is not limited to this. Any person skilled in the art can easily make the invention within the technical scope disclosed by the present invention. Any change or replacement is considered to be covered by the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (15)

A method for quantitative myocardial magnetic resonance imaging, including: Every recovery period, under the control of ECG gating signals and respiratory navigation signals, at least the following signal acquisition operations are performed: In the first heartbeat, when it is determined according to the breathing navigation signal that the current moment meets a predetermined condition, collect a first image signal; In the second heartbeat, after a saturation pulse with a delay time of Tsat2 is used, and when the current moment is determined to meet a predetermined condition according to the breathing navigation signal, a second image signal is acquired; In the third heartbeat, a third image signal is acquired after a saturation pulse with a delay time of Tsat3 is used and the current moment is determined to meet a predetermined condition based on the respiratory navigation signal, where Tsat3 ≠ Tsat2; In the fourth heartbeat, after a saturation pulse with a delay time of Tsat4 is used, and the current image is determined to meet a predetermined condition according to the breathing navigation signal, a fourth image signal is acquired; In the fifth heartbeat, the saturation pulse using a delay time and the echo time is Techo5 Tsat5 after a pulse interval T ₂ of the preparation, and the fifth image signal acquired in the case where the current time satisfies the predetermined condition of the determination in accordance with the respiratory navigation signals, Among them, Tsat5 = Tsat4; In the sixth heartbeat, using the delay time and the echo time Tsat6 saturation pulse interval of T ₂ of Techo6 after preparation pulses, and the sixth acquisition in the case where the image signal is the current time satisfies the predetermined condition of the determination in accordance with the respiratory navigation signals, Among them, Tsat6 = Tsat5 = Tsat4, Techo6 ≠ Techo4, Techo6 ≠ Techo5, Techo5 ≠ Techo4, Techo4 is the echo time interval of the T ₂ preparation pulse used in the fourth heartbeat, and when not used in the fourth heartbeat When T _{2 is} ready to pulse, Techo4 = 0; The parameter T _{1 is} determined according to the i-th image signal and the delay time Tsati of the saturation pulse corresponding to the i-th image signal, where i = 1, 2, 3, and when i = 1, Tsati is infinite; and according to the j-th image signal And the delay time Tsatj and T ₂ of the saturation pulse corresponding to the j-th image signal, the echo time interval Techoj of the preparation pulse determines the parameter T ₂ , where j = 4, 5, 6; A quantitative myocardial magnetic resonance image is generated based on the parameter T ₁ and the parameter T ₂ . The method of claim 1, wherein the signal acquisition operation further comprises at least one of the following operations: In the f1 heartbeat, after using a saturation pulse with a delay time of Tsatf1 and determining that the current time meets a predetermined condition according to the breathing navigation signal, the f1 image signal is collected, where Tsatf1 is not equal to the saturation pulse corresponding to other image signals Delay time, f1 is an integer not equal to 1, 2, 3, 4, 5 and 6; Wherein, the determination parameter T _{1 is} further based on the f1-th image signal and the Tsatf1. The method of claim 1, wherein the signal acquisition operation further comprises at least one of the following operations: In the f2 heartbeat, after using a saturation pulse with a delay time of Tsat2 or Tsat3, and after determining that the current time meets a predetermined condition according to the breathing navigation signal, the second image signal or the third image signal corresponding to the saturation pulse is acquired again , F2 is an integer not equal to 1, 2, 3, 4, 5 and 6. The method of claim 1, wherein the signal acquisition operation further comprises at least one of the following operations: In the first g1 heart beat, after using the delay time of the saturation pulse and the echo time Tsatg1 interval of Techog1 T ₂ of the preparation pulses and acquisition of g1 image signal in a case where the current time satisfies the predetermined condition of the respiratory navigation signal is determined according to, Among them, Tsatg1 = Tsat3, Techog1 is not equal to the echo time interval of the T ₂ preparation pulse corresponding to other image signals, and g1 is an integer not equal to 1, 2, 3, 4, 5, and 6; The determination parameter T _{2 is} further based on the g1-th image signal and the Techog1. The method of claim 1, wherein the signal acquisition operation further comprises at least one of the following operations: In the g2 heartbeat, after using a saturation pulse with a delay time of Tsat4 and a T ₂ preparation pulse with an echo time interval of Techo4 or using a saturation pulse with a delay time of Tsat 5 and a T ₂ preparation pulse with an echo time interval of Techo5, And when it is determined according to the breathing navigation signal that the current moment meets a predetermined condition, a fourth image signal or a fifth image signal corresponding to the saturation pulse is acquired again, and g2 is an integer not equal to 1, 2, 3, 4, 5, and 6. The method according to claim 1, wherein in the signal acquisition operation, before the first heartbeat, the method further comprises the following operations: In a heartbeat, when it is determined that the current time does not meet the predetermined conditions according to the breathing navigation signal, wait for the next heartbeat to perform a judgment operation again according to the breathing navigation signal and perform a corresponding image signal acquisition operation of the current heartbeat according to the judgment result. The method according to claim 1 or 6, wherein, in the signal acquisition operation, in the second heartbeat, the third heartbeat, the fourth heartbeat, the fifth heartbeat, and the sixth Before one or more of the heartbeats, the following operations are also included: In a heartbeat, when it is determined that the current time does not meet the predetermined conditions according to the breathing navigation signal, acquire an image signal and invalidate the acquired image signal, and wait for the next heartbeat to perform the judgment operation again based on the breathing navigation signal and The corresponding image signal acquisition operation of the current heartbeat is performed according to the judgment result. The method according to claim 1, wherein said acquiring a first image signal, said acquiring a second image signal, said acquiring a third image signal, said acquiring a fourth image signal, and said acquiring a fifth image signal And the data acquisition method of acquiring the sixth image signal uses a damaged gradient echo, balanced steady-state free precession, or gradient spin echo. The method according to claim 1, wherein, in the signal acquisition operation, the acquisition of a first image signal, the acquisition of a second image signal, the acquisition of a third image signal, and the acquisition of a fourth image Before the signal, the acquisition of the fifth image signal, and the acquisition of the sixth image signal, respectively, performing a liposuction operation. The method of claim 1, wherein: The Tsat3 is 90% to 100% of the maximum time interval Tmax allowed by the system, and the Tsat2 is 35% to 70% of the Tmax; The Tsat4 is 90% to 100% of the Tmax, and The Techo6 is 90 to 110% of the estimated value of T ₂ of the myocardium, the Techo5 said Techo6 of 35-70% or the minimum echo time system allows preparation pulse interval T _2. The method according to claim 1, wherein the recovery period includes n heartbeats, where n is a smallest integer greater than or equal to N / (60 / HR), and N is a length of time that allows the magnetization vector to be recovered, and the unit is Second, HR is the heart rate, and the unit is heartbeat / minute. The method according to claim 1, wherein said determining comprises determining parameters of the parameter T ₁ T ₁ according to the formula,

Among them, S ₀ is the signal of the longitudinal magnetization vector in the equilibrium state, S _i and Tsati are respectively the delay time of the i-th image signal and its corresponding saturation pulse, i = 1, 2, 3. The method according to claim 1, wherein said determining comprises determining parameters of the parameter T ₂ T ₂ according to the formula,

Wherein the longitudinal magnetization vector S _M is the delay time is the saturation pulse Tsat4 under the action signal, _j and S j-th Tehoj image signal and its corresponding preparation pulse echo time interval T _2, j = 4, 5, 6. A device for quantitative myocardial magnetic resonance imaging, comprising a processor and a memory, wherein the memory stores computer program instructions, and the computer program instructions are used by the processor to execute the computer program instructions as claimed in claims 1 to The quantitative myocardial magnetic resonance imaging method according to any one of 13. A storage medium stores program instructions on the storage medium, and the program instructions are used to execute the quantitative myocardial magnetic resonance imaging method according to any one of claims 1 to 13 when running.

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